Belowground Nutrient Dynamics Following Three Harvest Intensities on the Pearl River Floodplain, Mississippi
Abstract: The influence of clear and partial cut harvests on belowground nutrient cycling processes was examined on the Pearl River floodplain, Mississippi. Foci examined by this study included fine root biomass and detritus, fine root production, fine root nutrient contents, soil respiration rates, and microbial biomass C, N, and P during the first year post-harvest. Both the clearcut and partial cut initially reduced fine root biomass; however, fine root biomass levels within each treatment did not differ at this study’s conclusion. Bimonthly fine root production within both the clearcut and partial cut declined initially following harvest; however, net primary production was greatest within the clearcut, followed by the partial cut, and lowest within the control. Soil respiration rates showed strong seasonal trends; however, increased soil respiration rates within the clearcut and partial cut were not found until almost 1 yr post-harvest. Decreased microbial biomass C levels were observed following both harvests. Only the clearcut treatment significantly reduced microbial biomass N. No treatment effects were found regarding microbial biomass P. Herbaceous and woody vegetation recolonization was vigorous within the clearcut and partial cut harvests, strongly influencing fine root production levels and soil respiration rates. It appears that fine roots from naturally recolonizing vegetation play a large role in belowground C storage following disturbance. The rapid increases in fine root production and biomass following both silvicultural methods indicates that, within these ecosystems, the negative infuences of harvesting on belowground C and nutrient pools may be short lived.